TOP1 and cancer: SLFN11 selectively augments the anti-cancer effects of anti-cancer agents that target DNA replication, such as topoisomerase (TOP) inhibitors (TOP1 inhibitors: camptothecin, topotecan and irinotecan; TOP2 inhibitors: etoposide, mitoxantrone and doxorubicin), alkylating agents (cisplatin and carboplatin) and DNA synthesis inhibitors (gemcitabine and cytarabine) [15, 16].